Aleutian Islands 2018 Report Card (pdf)Region-wide•The North Pacific Index (NPI) was strongly positive from fall 2017 into 2018 due to the relatively high sea level pressure in the region of the Aleutian Low, which was displaced to the northwest, over Siberia, and caused persistent warm winds from the southwest. Positive NPI is expected during La Niña, but its magnitude was greater than expected. • The Aleutians Islands region experienced suppressed storminess through fall and winter 2017/2018 across the region. •The Alaska Stream appears to have been relatively diffuse on the south side of the eastern Aleutian Islands. •Although the sea surface temperatures cooled in 2018, relative to the 2014-2017 warm period, the overall temperature was still warm due to heat retention throughout the water column.
Figure 3: Western Aleutian Islands ecoregion indicators. * indicates time series updated in 2018. Central Aleutian Islands Ecoregion 2018•The pelagic fish foraging guild biomass declined overall from 2016 to 2018. Decreases were seen in all species but walleye pollock. •The slight decrease in the fish apex predator foraging guild biomass from 2016 to 2018 was largely driven by arrowtooth and Kamchatka flounder. •The most recent data available for otters show no trend, in contrast to the steep decline during the early 2000s. •Counts of non-pup Steller sea lions remain below the long term mean although there is no significant trend in the past 5 years. •Both Adak and Atka schools in the central Aleutian Islands have experienced declining enrollment over the past 2 years, approaching the 10-student threshold that risks closure of the schools, which would have negative impacts on the communities. •The amount of area trawled has increased since 2012, which was the last year of a dramatic 4- year decline following measures aimed at increasing protection for Steller sea lions during 2012–2014. Also, commercial fishing patterns may reflect recent changes in economics, ownership, and fishing effort allocation.
Figure 4: Central Aleutian Islands ecoregion indicators. * indicates time series updated in 2018. Eastern Aleutian Islands Ecoregion 2018•Relative abundances of gadids and Ammodytes (sand lance) in prey brought back to feed puffin chicks have shown opposite trends. Sand lance were above the long-term average in 2018. Puffins also had high reproductive success, indicating that forage fish were sufficient to support chick-rearing. •Pollock, Atka mackerel, Pacific ocean perch, and northern rockfish all contributed to the increase in fish pelagic forager biomass from 2016 to 2018. This represents a gradual increase since the low estimate in 2012. • Fish apex predator foraging guild biomass increased from the low values in 2012. Pacific cod and arrowtooth flounder contributed most to the increase. • There are no available data for otters in the eastern Aleutians ecoregion. •In contrast to the other ecoregions, non-pup counts of Steller sea lions remained high during the last count in 2015. The recent estimates have been above the long-term mean and are continuing an increasing trend. Counts were largely stable through the 1990s, but increased at a rate of 3% per year between 2000 and 2008. • School enrollment increased overall in the past 2 years, although there is still an overall decrease in the 5-year trend because of the steep decline in enrollment in 2016. The increase in the past 2 years is primarily due to Unalaska, whereas the small communities have either closed schools (Nikolski) or are at risk of closure (False Pass and Akutan). •The amount of area trawled increased slightly in 2018 to above the long-term average.
Figure 5: Eastern Aleutian Islands ecoregion indicators. * indicates time series updated in 2018. |
Aleutian Island Report Card - 2018
1 s.d. above mean